H1B -- Change from full time to part time employment

My daughter is working as a dentist on H1B full time 40 hrs/week. Due to Coronavirus pandemic, there are very few patients now in clinic resulting in huge decline in income in dental clinics. Her employer says that in present circumstances he cannot afford to pay her as stipulated in LCA. He wants to file amended LCA putting her as part time employee. Will that affect her H1B status or her H1B status will be maintained? Is there any minimum number of hours she has to work to keep her H1B status?

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